1. Field of the Invention
The present invention relates to a process of preparing commercial quantities of glucose and/or fructose from sucrose and a reactor for practicing same. In particular the present invention relates to a process for preparing glucose and/or fructose from sucrose by contacting sucrose with a fructosyltransferase and/or a glucosyltransferase, followed by isolating glucose and a polyfructan, fructose and a polyglucan or both.
2. Description of the Background
Glucose and fructose are saccharides that are found throughout nature, either as monosaccharides or incorporated into polysaccharides. Glucose is used clinically as a fluid and nutrient replenisher, as a carbon source in the culturing of microorganisms and is widely used as a food additive. Fructose is also clinically used as a fluid and nutrient replenisher and widely as a food additive.
Glucose has been prepared commercially from starch (Dean, Gottfried, Advan. Carbohyd. Chem. 5, 127 (1950) and by acid hydrolysis of sucrose. Fructose has been prepared by hydrolysis of inulin (Bates et al. Natl.Bur. Std. (U.S.) Circ. C440, 39 (1942)), from dextrose (Cantor, Hobbs U.S. Pat. No. 2,354,664) and enzymatically from sucrose (Koepsell et al. U.S. Pat. No. 2,729,587). In spite of the availability of the starting materials for preparing glucose and fructose, the cost of these materials remains high, relative to the cost of the starting materials. Accordingly, commercial syntheses of both glucose and fructose can be improved.
Inulins are polysaccharides belonging to the polyfructan group and occur in many different plants including, for example, Jerusalem artichokes, dahlia tubers, and chicory roots. Inulins are comprised of .beta.-2,1-linked fructose chains, linked to an .alpha. D-glucoside; they have a linear structure and typically comprise many .beta.-O-fructofuranose units. The average chain length and molecular weight distribution will depend on both the plant species, the growth phase, and the preparation method. Average chain lengths of 10 to 25 are common, in which case the individual units have about 9 to 24 fructose units.
The properties of an inulin will vary depending on the chain length. Compositions comprising short chain inulins having a degree of polymerization of about 3 to 7 fructose units have been used as reduced calorie sugar substitutes (DE 4,003,140).
Polyglucans are polysacharides of glucose units, typically connected by .alpha.-1,3, .alpha.-1,6, .beta.-1,2, .beta.-1,3, and .beta.-1,4 linkages. A class of polyglucans comprised of .alpha.-1,3 and .alpha.-1,6 linkages are produced in nature by many oral bacteria flora, such as S. mutans, and are believed to assist in the colonization of the oral cavity by these organisms, which produce the disease state of dental caries. The polyglucan based entirely on .beta.-1,4 linkages is produced by plants, as cellulose. The polyglucan based entirely on .beta.-1,3 linkages is produced by plants, as callose. Another polyglucan based on random linkages, typically terminating with a sorbitol, is known as polydextrose and is used as a food bulking agent.
Stoudt et al. U.S. Pat. No. 4,340,673 report a modified glucan prepared biosynthetically from a glucosyltransferase, sucrose and an endo .alpha.-1,3glucan-3-glucanohydrolase for the modification of dental plaque development.
Gaffar et al. U.S. Pat. No. 5,095,106 and U.S. Pat. No. 5,002,759 report an oligosaccharide having at least one fucose moiety or a galactose moiety, said oligosaccharide which is free of digalactose and N-acetlyneuraminyl lactose, for inhibiting adherence of Streptococcus pyogenes to pharyngeal and oral mucosa cells.
Taubman et al. U.S. Pat. No. 4,150,116 report that Strepotcoccus mutan colonization may be inhibited by immunization with a purified form of a glucosyltranferase.
Eigen et al. U.S. Pat. No. 4,619,825 report plaque inhibition by treatment with a water dispersion of emulsan.
Hillman et al. U.S. Pat. No. 4,133,875 report that an effector strain of Streptococcus mutans may be effective to control the incidence and severity of dental caries.
In the area of fructose production Kerkhoffs et al U.S. Pat. No. 4,277,563 report the isolation of fructose by hydrolysis of a polyfructan such as inulin.
Bichsel et al. U.S. Pat. No. 4,263,052 report the production of fructose by hydrolysis of a fructofuranoside such as sucrose and enrichment in fructose by precipitation of a calcium-fructose complex.
Fan et al. U.S. Pat. No. 4,774,183 report that fructose can be isolated from a mixture of fructose and glucose by contacting with a microorganism such as Pullularia pullulans which preferentially utilizes glucose.
Bringer et al. U.S. Pat. No. 4,742,006 report the production of fructose from mixtures of fructose and glucose by contacting with a glucose decomposing mutant of Zymomonas mobilis.
In the area of glucose production, Nagle et al. U.S. Pat. No. 4,637,835 report the preparation of glucose and other saccharides from an .alpha.-cellulose using a calcium chloride catalyst and hydrogen ions.
Miyawaki et al. U.S. Pat. No. 5,524,075 report the production of high purity glucose by saccharifying liquefied starch with an enzyme.
Venkatasubramanian et al. U.S. Pat. No. 4,299,677 report the direct separation of fructose and glucose from a mixture of glucose and fructose by ion exchange membranes.
Harada et al. U.S. Pat. No. 5,169,679 report the use of polyfrucans composed mainly of .beta.-2,1 bonds having a molecular weight of from 2,000 to 20,000,000 as food additives such as, for example, bulking agents or fat substitutes, for producing low calorie foods.
Kurz et al. U.S. Pat. No. 5,478,732 report a method for obtaining intermediate-chain inulins (e.g. a degree of polymerization of 10-12) by treatment of crude inulin suspensions with a hydrolase enzyme. During the enzymatic treatment, short-chain components are degraded to mono- and disaccharides while long-chain inulins are separated off, then converted to a dry form.
Adachi et al. report in U.S. Pat. No. 4,681,771 that when sucrose (G-F) is contacted with an enzyme having fructose transferring activity (hereinafter referred to as a fructosyltransferase), a low caloric, low-cariogenic sweetener composition is obtained which comprises glucose, sucrose, the trisaccharide (GF.sub.2), the tetrasaccharide (GF.sub.3) as well as minor amounts of fructose, pentasaccharide (GF.sub.4) and hexasaccharide (GF.sub.5). The amount of higher inulins drops off dramatically, the majority fraction being inulin GF.sub.2-3.
Kono et al. U.S. Pat. No. 5,314,810 report that the half-life of an immobilized fructosyltransferase used in the reaction of sucrose can be improved by support on a granular carrier such as chitosan derivative or an anion exchange resin. Such a supported enzyme is reported to allow for the industrial production of a low cariogenic sweetener composition.
Heady U.S. Pat. No. 4,317,880 reports the production of novel fructose polymers and high fructose syrups from sucrose by the combined action of a fructosyl transferase enzyme and a glucose isomerase enzyme preparation.
Heady U.S. Pat. No. 4,335,207 reports a two step process for the preparation of fructose polymers and ethyl alcohol from sucrose by contacting with a fructosyl transferase enzyme followed by fermentation with a yeast preparation.
Present methods for preparation of glucose and fructose from sucrose however, have suffered from poor efficiency, such that the production of commercial quantities of glucose and fructose can be improved.
In addition, there remains a need for processes for preparing commercial quantities of polysaccharides such as inulins and in particular GF.sub.4-5 and polyglucans such as polydextrose substitutes, cellulose, starch, and those which may be used for the treatment of dental caries.